Aluminum base bearing alloy and a bearing element comprising a running layer formed by the alloy

ABSTRACT

The invention relates to an aluminum alloy, to a plain bearing and to a method of manufacturing a layer, particularly for a plain bearing, to which there is added as a main alloy component tin ( 14 ) and a hard material ( 15 ) from at least one first element group containing iron, manganese, nickel, chromium, cobalt, copper or platinum, magnesium, or antimony. Added to the aluminum alloy from the first elementary group is a quantity of elements for forming inter-metallic phases, e.g. aluminide formation, in the boundary areas of the matrix, and further at least one further element from a second element group containing manganese, antimony, chromium, tungsten, niobium, vanadium, cobalt, silver, molybdenum of zirconium, for substituting a portion at least of a hard material of the first element group in order to form approximately spherical or cuboid aluminides ( 7 ).

The invention relates to an aluminum base bearing alloy and a bearingelement comprising a running layer formed by the alloy.

In order to avoid the disadvantages of silicon-containing aluminium-tinalloys in view of a lower fatigue strength due to the stressconcentration of the silicon particles on the one hand and thechip-removing effect of the silicon particles in the area of the bearingsurface on the other hand, the addition of silicon to the alloy isfrequently omitted. In order to improve the mechanical properties ofsilicon-free aluminium alloys with a high tin content of 35 to 65% byweight, it has already been proposed according to DE-A1-42 31 862 A1, inaddition to 0.1 to 1.5% by weight of copper in order to improve thefatigue resistance on the one hand, to add to the alloy on the one handlead and bismuth in an overall quantity of 0.5 to 10% by weight, otherhand at least one of the elements manganese, nickel, silver, magnesium,antimony and zinc in an overall quantity of a maximum 5% by weight. Dueto the high tin content however, upon hardening of the alloy from themelt, there is formed a substantially coherent tin network, whichconsiderably impairs the structural strength of the plain bearingmaterial and its capacity for shaping, which is of importance with aview to the conventional plating of these cast alloys with steel, and ofthe shaping stages involved therewith. In addition, as the tin contentincreases, the network structure of the tin in the aluminium matrix hasan increasing influence on the mechanical properties of the plainbearing material.

Attempts have also already been made to improve the mechanicalproperties of aluminium-tin alloys by adding to these alloys well-knownmatrix-reinforcing elements such for example as copper, manganese,nickel, magnesium and tin. Such aluminium-tin alloys are known amongothers from DE 42 01 793 A.

Furthermore it is already known, according to DE 32 49 133 C2, togenerate a heterogenous structure in aluminium-tin alloys by means of athermal aftertreatment. By means of this aftertreatment hard particles,e.g. silicon or aluminides, are separated, enabling favourable wearproperties with quite specific distribution functions.

In the case of cast alloys, according to DE-C2-36 40 698, it isnecessary in order to establish the final dimension of the individuallayers with shaping during the plating with steel, to undertake variousshaping stages, which also require various connected thermal treatments.This compound production and in particular the various shaping stageshave until now prevented the use of strength-increasing alloyingmeasures.

A layer material for plain bearing elements with a tin content ofbetween 0.5% by weight and 20% by weight is known from DE 40 04 703 A1.By means of the addition of nickel and manganese an attempt issubstantially made to produce manganese-containing hard particles inorder to improve the wearing properties of such a plain bearing element.A disadvantage here is however that, despite the addition of elementsforming hard particles, the tin content remains restricted to up to 20%by weight.

Finally, DE 43 32 433 A1 describes a multilayer plain bearing with abearing alloy layer on a basis of aluminium and tin. Here also the tincontent of the aluminium alloy for the bearing alloy layer is restrictedto 20% by weight, and the attempt is made to improve the strengthproperties of such an aluminium-tin alloy by adding to the alloyelements forming hard material.

The object underlying the invention is to provide an aluminium alloywhose mechanical properties are clearly better, even at higher tincontents.

The object is achieved with an Al base bearing alloy with an alloymatrix consisting of 16 to 32 wt-% Sn as a main alloy component, atleast 1.4 wt-% Cu, at least two elements selected from a first elementgroup consisting of Mn, Ni and Fe in a quantity of between 40% and 200%of the Cu quantity, and at least one element selected from a secondelement group consisting of Cr, Co, Zr, Mg, Sb, W, Nb, V and Mo, thealloy matrix containing 0.1 to 1.5 wt-% Cr, at least 0.2 wt-% of a totalof Cr, Co and Zr, this total being at most 200 wt-% of the Fe and Nicontent, 0.1 to 1 wt-% of a total of Zr, Mg, Sb, W, Nb, V and Mo, theratio of Co to Fe in the alloy matrix being 1:1 to 0.2:1, and theremainder being Al with the usual impurities, wherein the elements ofthe first and second element groups form approximately spherical orcuboid aluminide grains in a proportion, by volume, of from 0.15% to 5%of an interrupted Sn-network structure, the aluminide grains having amaximum of 70% of the average circumferential length of the visiblematrix grain boundaries, and at least 15% of the Sn grains being presentin a size ratio of 1:1 to the aluminide grains.

Also of advantage is a bearing consisting of a steel support layer, arunning layer formed by the above-described Al base bearing alloy, andan intermediate layer between the steel support and running layers.

The amount of Zr in the alloy matrix is 0.1% to 1.0 wt %, preferablybetween 0.15% and 0.5 wt %. The weight proportion is a maximum 10% foran element of the third element group of Pb, Bi, Cd and In.

The invention will be explained in more detail in the following withreference to the views in the drawings. Shown are:

FIG. 1: a schematic micrograph of a previous bearing material for plainbearings on an aluminium basis according to prior art;

FIG. 2: a schematic micrograph of a bearing material according to theinvention;

FIG. 3: a three-dimensional view of variously-formed aluminides, theirinitial and in their final condition;

FIG. 4: a plain bearing according to the invention, designed as a shellin a two-layer structure, shown schematically;

FIG. 5: a further plain bearing according to the invention, designed asa shell in a three-layer configuration, shown schematically;

FIG. 6: a graph of the bearing durability of plain bearings with runningand intermediate layers plated onto a steel layer, and consisting ofvarious aluminium alloys, with a bearing load changing over the runningtime;

FIG. 7: a graph showing the hardness behaviour in the individual layersof a plain bearing over the operational time;

FIG. 8: a graph according to FIG. 7 for a plain bearing with layersdesigned according to the invention.

As shown by FIG. 1, which illustrates a conventional material 1 knownfrom prior art for plain bearings on an aluminium basis with 20% byweight of tin and 1% by weight of copper, the tin phase 2 in the alloymatrix 3 forms a substantially cohesive tin network 4, whichdisadvantageously influences the mechanical properties of this material1.

This network structure could be broken up in the case of a bearingmaterial 5 for plain bearings according to the invention, as shown inFIGS. 2 and 3.

The bearing material 5 shown according to the invention contains, inaddition to 23% by weight of tin, 1.8% by weight of copper, 0.6% byweight of manganese, 0.23% by weight of iron, 0.17% by weight of cobalt,0.14% by weight of chromium and 0.1% by weight of zircon. Despite thehigher tin proportion, a clearly less cohesive tin structure 6 results,because the separated tin phase 2 is interrupted by aluminides 7 orinter-metallic phases of manganese and iron, to which the tin phase 2 isapplied. As is more clearly seen from FIG. 3, these aluminides 7,despite their composition, do not have a disadvantageous effect on themechanical properties of the bearing material 5, because due to theaddition of manganese and/or cobalt and/or chromium and/or zircon inspecific quantities, the stress concentration otherwise caused by anoutstanding longitudinal extension 8 of the aluminides 7 shown in dottedlines, could be suppressed by their alteration into the shown sphericalor cuboid spatial shape and shorter main dimension or length 9.

Naturally, the bearing material 5 according to the invention can besubjected to a conventional thermal and shaping aftertreatment, in orderfurther to improve the mechanical properties. Due to the effect of acorresponding plastic deformation, the aluminides 7 can be brought intosolution at a comparatively low treatment temperature, in order then tosubject the bearing material 5 to a separation hardening of a startingtreatment.

In order to indicate the special properties of the bearing material 5according to the invention, such a bearing material 5 was compared witha conventional material 1 for a plain bearing. For this purpose thematerials to be compared were cast under identical conditions to form astrip by horizontal extrusion casting, said strip having a cross-sectionof 10 mm×100 mm.

Due to the discharge conditions selected, a heat removal of between 3.4and 3.7 J/s was ensured for hardening.

In addition to aluminium, the conventional material 1 consisted of 20%by weight of tin, 0.9% by weight of copper as a main alloy component,with the other impurities normal in aluminium.

The alloy according to the invention or the bearing material 5 had inaddition to aluminium as a main alloy component 23% by weight of tin,1.8% by weight of copper, 0.6% by weight of manganese, 0.23% by weightof iron, 0.14% by weight of chromium, 0.17% by weight of cobalt, 0.1% byweight of zircon and the further impurities normal in aluminium. In thebearing material 5, the tin network 4, contrary to the comparativealloy, was present in a substantially interrupted form, so that in thealloy according to the invention, despite the clearly higher tincontent, a better structural strength was revealed. Accordingly, anincrease in the Brinell hardness in the cast condition of at least 5points was measured.

In order to test the deformability, both materials were subjected to anannealing treatment of 3 hours at 350° C. After subsequent grinding toremove the casting crust from the samples, the samples had across-section of 8 mm×80 mm. During a rolling shaping treatment withoutintermediate annealing, the previous material 1 allowed only adeformation of a maximum 25% in one single pass, the first cracksalready appearing, which upon a reduction per pass of up to 35%, led tostrips which could no longer be used.

In the bearing material 5 according to the invention, at a deformationof 20% the first cracks were already recognised, yet as the passstrength increased, these cracks grew considerably more slowly, so thatat a reduction per pass of 40%, the strip could be used without problemsexcept for a narrow lateral area.

A further shaping test comprised testing the number, permissible withoutintermediate annealing, of consequently-executed rolling operations witha respective reduction per pass of 5%. In the previously usual material1, deformation had to be stopped after 8 to 10 passes. This correspondsto a maximum overall deformation of scarcely more than 40%. By means ofhardness measurements carried out after each pass on the rolled surface,it was observed that the comparative alloy had a maximum hardness after6 passes. During the following passes, a partial reduction in thehardness was even noticed, which gives evidence of structural damage.

In the bearing material 5 according to the invention, on the contrary, aparticularly marked increase in the hardness was measured up to theeighth roller pass, after which the hardness remained constant until thetwelfth to fourteenth roller pass and only decreased after thethirteenth to fifteenth roller pass. With a corresponding overalldeformation of 48% to 53%, further deformation was no longer possibledue to cracking.

FIG. 4 shows a possible design of a shell-shaped bearing member 10 of aplain bearing 11, in which the bearing member 10 consists of a supportlayer 12, which is normally produced from a metallic material, forexample steel, and which forms a receiving means for a shell-shapedrunning layer 13. In order to form plain bearings 11, which serve toprovide a rotarily-movable bearing for machine shafts, engine shafts,etc., two such identical bearing members 10, as shown in dotted lines,are combined to form a bearing ring, and are normally inserted into abearing casing containing this bearing ring with correspondingform-fitting and security against twisting.

The running layer 13 is connected immobile with the support layer 12,e.g. is plated on, rolled on, welded, glued, etc., and in theconstruction according to the invention preferably consists of analuminium alloy with a series of possible alloy components in order toachieve a high bearing stress resistance with respect to temperature,strength, running time and with a minimised coefficient of friction inconjunction with suitable materials for the machine shafts, engineshafts, etc.

According to a preferred construction, the running layer 13 consists ofan aluminium alloy, in which the main alloy component is made up of tin14 and a hard material 15 of at least one element 16 of a first elementgroup containing iron, manganese, nickel, chromium, cobalt, copper orplatinum, magnesium, antimony. Added to the aluminium alloy of the firstelement group is a quantity of elements 16, so that inter-metallicphases, e.g. aluminides 7, form in the boundary areas of the matrix. Atleast one further element 16 of a second element group containingmanganese, antimony, chromium, tungsten, niobium, vanadium, cobalt,molybdenum or zirconium, at least a portion of the hard material 15 ofthe first element group is substituted, so that the aluminides 7 areconverted into an approximately spherical or cuboid three-dimensionalshape.

Furthermore, at least one element 16 from the group comprising calcium,lithium, silicon and titanium can be contained in the aluminium alloyaccording to the invention.

FIG. 5 shows another bearing member 10 with the support layer 12 and therunning layer 13, in which there is disposed between the support layer12 and the running layer 13 an intermediate layer 18, if necessary as amiddle layer or binding layer. The intermediate layer 18 with therunning layer 13 connected immobile therewith, in this construction,with coordination of the alloy components, the intermediate layer 18being preferably formed by an aluminium alloy, form a composite materialwhich decisively influences the properties sought after for the bearingmember 10.

According to another preferred design for a composite material,particularly for a plain bearing 11 comprising a running layer 13 and anintermediate layer 18, these contain as main alloy components at leastone element 16 of an alloy element group containing tin, zinc, copper,lead, bismuth, cadmium and/or indium, the main alloy element of therunning layer 13 being tin 14, and that of the intermediate layer beingzinc. At least one further element of an alloy element group containingiron, manganese, copper, nickel, chromium is added, in order to maintaina differential between the alterations in strength in the running layer13 and in the intermediate layer 18 with approximately identicalpressure and/or temperature stress between 0% and 20%. Furthermore, therunning layer 13 and the intermediate layer 18 are hardenable. Astrength of the intermediate layer 18 is identical to or greater thanthe strength of the running layer 13.

A further preferred design for a composite material, particularly for aplain bearing 11, consisting of the running layer 13 and of theintermediate layer 18, contains as main alloy components at least oneelement from an alloy element group containing tin, zinc, copper, lead,bismuth, cadmium and/or indium. This composite material, which forms atleast a part of a plain bearing 11, enables formation of theintermediate layer 18 and/or of the running layer 13, so that they havea strength which comes to 70% to 99.5% of the peak strength of therespective running layer 13 or of the intermediate layer 18.

It is naturally also known from prior art to manufacture plain bearings11 in an enclosed annular form, these being cast as a ring in accordancewith predetermined rough dimensions, or being shaped into correspondingrings from a rolled or extruded profile, and being connected,particularly welded, at the resultant abutting points, at the opposedend faces, to form an uninterrupted ring. For such plain bearings 11also, the materials 1 named above for the intermediate layer 18 and/orthe running layer 13 may be used.

Such plain bearings 11 are frequently produced by a composite materialtechnique in which the various layers are connected together immobile,preferably by being plated together. Such plain bearings 11,prefabricated in strip form or in ring form, are brought to therespective dimensions with corresponding bearing tolerances and assemblytolerances by subsequent fine machining, and are inserted by methods ofattachment technology in bearing receiving means of bearings or motorcasings, and are held secure against rotation by securing members oralso by gluing.

FIG. 6 shows a graph in which the load in bar is entered on theabscissa, and the running time in minutes with a logarithmic division isentered on the ordinate.

As is known, because of load on a bearing member 10, particularly thetemperature and pressure load during a so-called running-in phase andeven thereafter, there is an alteration in strength, the alterationbeing dependent on the ingredients of the alloy. After this so-calledrunning-in period and reaching specific threshold values, no furthersubstantial alterations in the strength occur until the end of a runningtime is reached, at which such a bearing becomes unusable due tomaterial fatigue.

With reference to the examples of various layer structures described inthe following for such plain bearings 11, the bearing structureaccording to the invention and its effect on the bearing service life isexplained.

EXAMPLE 1

In the case of this plain bearing 11 the support layer 12 is made of asteel, and the running layer 13 of an aluminium alloy, particularlyAlZn4.5, which is connected immobile to the support layer 12.

EXAMPLE 2

In the case of this plain bearing 11 the support layer 12 is formed froma steel. Applied to the support layer 12 is the intermediate layer 18 ofpure aluminium, and upon this the running layer 13 of an aluminium Snalloy, for example AlSn6Cu or AlSn20Cu.

EXAMPLE 3

In this plain bearing 11, the support layer 12 is formed from a steel.Applied by sputtering to the support layer 12 is the intermediate layer18 comprising a CuPb-alloy and upon this the running layer 13 of AlSn20.

EXAMPLE 4

In this construction of a plain bearing 11, the support layer 12consists of steel. In the first variant construction, there is appliedto this support layer 12 of steel an intermediate layer 18 of purealuminium, and in turn on this a running layer 13 according to theinvention.

In order now to be able to test the bearing behaviour of a plain bearing11 and to assign it to various categories of use, the bearing durabilitybehaviour can be ascertained and tested with reference to predeterminedtest methods. In order to simulate the load for example with a shaftrotating at a predetermined rotary speed, the load acting on the bearingcasing is applied, operation being for example, in dependence on thebearing size in the cylinder size used, with a hydraulic pressure of 75bar. When the maximum bearing load is then achieved, the test is carriedon until the bearing is damaged by crushing of the running layer 13 orformation of scores in the area of the running or intermediate layers13, 18 or by friction to such an extent that it must be replaced. Thedefinition of the point at which this damage is so assessed that thebearing is no longer usable, is to be ascertained in detail before eachindividual sequence of tests.

The graph now shows the bearing durability behaviour of the designs ofthe individual plain bearings 11 described previously with reference toExamples 1 to 4.

As will be seen from observation of the graph, which represents amongother things a simple plain bearing 11 known from prior art according toExample 1, such a plain bearing 11 fails due to abrasion of the bearingpoint before reaching the maximum stress at point in time 19, as thegraph shows.

Better bearing resistance behaviour is already achieved with a design,likewise known from prior art, of a plain bearing 11 with a three-layerstructure, in which the support layer 12 is of steel, the intermediatelayer 18 of pure aluminium and the running layer 13 of an aluminiumalloy alloyed with tin 14, in accordance with Example 2.

Whilst the aluminium alloy with the lower tin content likewise failsbefore reaching the maximum stress at point in time 20, thehigher-alloyed aluminium alloy resists the maximum load over a longerperiod as far as a point in time 21, at which the bearing is crushed, orto a point in time 22, in which the bearing is abraded.

Extremely long service life of a bearing is achieved as is known fromprior art by a bearing structure according to Example 3, as such abearing, after a running time of 10,000 minutes, at which also point intime 23 is entered, the plain bearing 11 is still usable.

Such bearings, which achieve such a high service life in thiscomparative test, are termed “fatigue-tested specimens without rupture”.

Finally, points in time 24 and 25 show the test results for a bearingstructure, according to Example 4, in which the intermediate layer 18consists of pure aluminium and the running layer 13 of an aluminiumalloy according to the invention. With this, in contrast to the designof the bearing according to Example 3, a considerable increase in thebearing service life was achieved with a substantially simpler bearingstructure.

A design is likewise usable, in which the intermediate layer 18 containsas a main alloy component zinc, and the running layer 13 as a main alloycomponent tin 14, as likewise indicated in Example 4.

In a further test, there were applied to the support layer 12 of steelan intermediate layer 18 of AlZn4.5, a running layer 13 of AlSn20Cu. Aplain bearing 11 designed in this way shows that it is ready for use upto point in time 26.

The best result is however achieved with a bearing structure in whichthe support layer 12 is again of steel and the intermediate layer of analuminium-zinc alloy particularly AlZn4.5, upon which a running layer 13with the aluminium alloy according to the invention is applied.

The surprising factor for the person skilled in the art was however thatin this combination, in which the intermediate layer 18 is alloyed withzinc and the running layer 13 according to the invention is used, a“fatigue-tested specimen without rupture” entered with a point in time27 in the graph, could be achieved with a bearing structure considerablysimpler and thus cheaper in comparison to the bearing structureaccording to Example 3.

FIGS. 7 and 8 show the alteration in the hardness over the operatingtime of a plain bearing in the form of illustrations, the configurationof hardness being dependent on the different composition between runninglayer 13 and intermediate layer 18.

As the support layer 12 of steel is always the same, this is no longerconsidered in the study, as also the hardness of the steel layerscarcely changes over the operational period.

The essential factor is rather that, depending on the alloy of therunning and intermediate layers 13 and 18, a different hardness results.

As already explained before, it is advantageous for a long-lastinginterruption-free operation and a long bearing service life if thealterations in hardness in the intermediate layer 18 and in the runninglayer 13 are roughly similar, i.e. only small differences occur between0% and 20% in the hardness alteration over the operational life.Favourable results for practice are achieved, if, as shown in the graphin FIG. 7, the aluminium alloy according to the invention, which isprovided with a high tin proportion, is used as the running layer 13,and pure aluminium as the intermediate layer 18. In this embodiment itis apparent that due to the hardening of the aluminium alloy accordingto the invention the hardness increases over the operational life, whilein contrast, as already known from prior art, due to the effects of heatand pressure, the pure aluminium loses its tensions, which cause higherstrength, and with increasing operational time become softer. Due to theselection of the increase in hardness in the running layer 13 inproportion to the decrease in hardness of the intermediate layer 18,despite this a positive overall result can be achieved, which enables ahigh service life, of keeping to the boundary values in the alterationin hardness over the operational time.

The configuration of the increase or reduction in hardness is shown inthe graph in FIG. 7 for the running layer 13 by the diagram line 28, andfor the intermediate layer by the diagram line 29. A surprisinglypositive result for the person skilled in the art is however afforded bya bearing structure with respect to the configuration of hardness overthe operational time, if, as the graph in FIG. 8 shows, the runninglayer 13 according to diagram line 30 and the intermediate layer 18, asthe diagram line 31 shows, are hardenable and if their hardnessincreases due to the temperature effect over the operational period, sothat only small or no differences at all in the alteration in hardnessoccur during the operational period. This is achieved by the aluminiumalloy, supplied with a high tin proportion and alloyed with additionalalloy components, in the running layer 13, and by the aluminium alloy ofthe intermediate layer 18, alloyed with tin 14, as already mentionedabove, by shaping and plating together, and the intermediate layer 18being connected to the support layer 12 of steel.

It will also be seen from the graph in FIG. 8 that in this case thegreater hardness of the intermediate layer, also shown by the bearingdurability behaviour in the diagram in FIG. 6, a high service life ofsuch a bearing is achieved.

List of Reference Numbers

1. material

2. tin phase

3. alloy matrix

4. tin network

5. bearing material

6. tin structure

7. aluminide

8. longitudinal extension

9. length

10. bearing member

11. plain bearing

12. support layer

13. running layer

14. tin

15. hard material

16. element

18. intermediate layer

19. point in time

20. point in time

21. point in time

22. point in time

23. point in time

24. point in time

25. point in time

26. point in time

27. point in time

28. diagram line

29. diagram line

30. diagram line

31. diagram line

What is claimed is:
 1. An Al base bearing alloy comprising an alloymatrix comprising 16 to 32 wt-% Sn as a main alloy component, at least1.4 wt-% Cu, at least two elements selected from a first element groupconsisting of Mn, Ni and Fe in a quantity of between 40% and 200% byweight of the Cu quantity, and the element Co, at least one elementselected from a second element group consisting of Cr, Mg, Sb, W, Nb, Vand Mo, the alloy matrix containing 0.1 to 1.5 wt-% Cr, at least 0.2wt-% of a total of Cr, and Co, this total being at most 200 wt-% of theFe and Ni content, 0.1 to 1 wt-% of Zr, at least 0.2 wt % to 200 wt % ofthe Fe or Ni content of a total of Mg, Sb, W, Nb, V and Mo, the ratio ofCo to Fe in the alloy matrix being 1:1 to 0.25:1, and the remainderbeing Al with the usual impurities, wherein the elements of Co and thefirst element group form approximately spherical or cuboid aluminidegrains in a proportion, by volume, of from 0.15% to 5% of an interruptedSn-network structure, the aluminide grains having a maximum of 70% ofthe average circumferential length of the visible matrix grainboundaries, and at least 15% of the Sn grains being present in a sizeratio of 1:1 to the aluminide grains.
 2. The Al base bearing alloy ofclaim 1, wherein the weight proportion of the two elements of the firstelement group is between 45% and 100% based on the Cu content.
 3. The Albase bearing alloy of claim 1, further comprising one element selectedfrom a third element group consisting of Pb, Bi, Cd and In, and anelement selected from a fourth element group consisting of Zn, Ca andLi, the proportion of each of the elements of the third group beingbetween 25 wt-% and 200 wt-% of the maximum solubility of the element inthe overall quantity of Sn, the overall proportion of these elementsbeing a minimum 100% and maximum 300% of the maximum solubility of theleast soluble element in Sn and the proportion of each of the elementsof the fourth group being between 10% and 100% of the maximum solubilityof the element in the overall quantity of Al, the overall proportion ofthe elements of the fourth group being at least 50% and at most 200% ofthe maximum solubility of the least soluble element of this group in Al.4. The Al base bearing alloy of claim 3, wherein the quantity of eachelement of the third element group is at most 10% by wt.
 5. The Al basebearing alloy of claim 1, wherein one element selected from a fifthelement group consisting of Si and Ti is added, the overall content ofthe fifth element group with at least one of the second element group isless than 100% of the Cu content.
 6. The Al base bearing alloy of claim1, wherein the weight ratio of Mn to Fe is between 4:1 and 2.5:1.
 7. TheAl base bearing alloy of claim 1, wherein the alloy matrix contains0.15% by wt to 0.8% by wt Cr.
 8. The Al base bearing alloy of claim 1,wherein the alloy matrix contains 0.15% by wt to 0.5% by wt Zr.
 9. TheAl base bearing alloy of claim 1, wherein the alloy matrix contains Niand Cr in a weight ratio of 0.5:1.
 10. The Al base bearing alloy ofclaim 1, wherein the alloy matrix contains Co and Fe in a weight ratioof 0.75:1 to 0.5:1.
 11. The Al base bearing alloy of claim 1, whereinthe proportion of Sn is between 22% by wt and 28% by wt.
 12. The Al basebearing alloy of claim 1, wherein the weight ratio of Mn to Fe isbetween 3.5:1 and 2.5:1.
 13. The Al base bearing alloy of claim 1,wherein Ni and Cr is added in a weight ratio of 0.2:1.
 14. A bearingelement consisting of a steel support layer, a running layer formed bythe Al base bearing alloy of claim 1, and an intermediate layer betweenthe steel support and running layer.
 15. The bearing element of claim14, wherein the running layer is hardenable and said running layer has astrength not exceeding the strength of the intermediate layer.
 16. Thebearing element of claim 14, wherein said intermediate layer is formedof pure Al.
 17. The bearing element of claim 14, wherein theintermediate layer is formed by an Al alloy containing as maincomponents at least one element selected from the group consisting ofFe, Mn, Ni, Cr, Co, Cu, Pt, Mg, Sb, Ag and Zn.